Internal-combustion engine



Jun 'lz, 192s. 1,673,280

A. F. EVANS INTERNAL COMBUSTION ENGINE File e 1927 2 Sheets-Sheet 'zzrang fl w 2395 June 12, 1928.

A. F. EVANS INTERNAL COMBUSTION ENGINE Filed Feb. 17, 1927 2 Sheets-Sheet 2 I ML TI TI Ill Patented June 12, 1928.

ARTHUR FREDERICK EVANS, 0F BARNES, ENGLAND.

INTERNAL-COMBUSTION ENGINE.

Application filed February 17, 1927, Serial No. 168,877, and in Great Britain March 3, 1926.

This invention relates to internal combustion engines of the Diesel type.

Internal combustion engines of the Diesel type and of powers below one thousand horse power for instance, have been foundto be proportionally long, taking into consideration the space generally available, when applied to merchant vessels and when compared with the steam engine and boiler they are intended to replace.

In this application the amount of width available is generally more than suflicient for the needs, the main object of my invention being to provide a propelling engine of the Diesel type that can be accommodated in an engine room of much shorter dimensions than is usually required although the engine itself will be wider.

Further, in a two stroke cycle engine of this kind some provision has to be made for pumping the scavenging air and 'parctice has shown that the most efficient method is to arrange for separate pumping cylinders, placed in line with the working cylinders and driven from the crank shaft.

Although this isin every way satisfactory from the mechanical point of view it further increases the length of the engine and therefore in order to eliminate the space occupied and the cost of construction the provision of this efiicient scavenge cylinder is often abandoned and a much less suitable method em; ployed.

It is a further object of my invention to provide an engine so constructed as to retain or embody this feature whereby an efiicient scavenging arrangement is provided and at the same time to reduce the total length of the engine, without adding to the complications or cost, thereby obtaining an engine which. offers considera le advantages.

According to the present invention I employ a two cylinder engine of the inverted beam type such as hereinafter referred to, having a scavenging pump placed under that cylinder which is remote from the crank and driven directly .or indirectly by the piston of this said cylinder.

Further, the cylinders are so arranged that the space between them is utilized as a scavenging air chamber in the walls of which the scavenging port and super-charge valve are located, the said super-charge valve being, for example, of the rotary or semi-rotary type operated by a through shaft.

The cylinders of the improved engine are preferably constructed in pairs forming a unit and in such manner that any number of units can be bolted together as required.

The accompanying drawings show one construction of engine embodying my invention.

gig. 1 is a vertical section of the engine, an

Fig. 2 is a sectional plan on line X X of Fig. 1.

In the construction shown I rovide two inverted two-stroke cycle cylin ersa and 6 preferably cast in one, the cylinders containing identical pistons a and a! respectively, fitted with short articulated piston rods e f.

The cylinders a and b are mounted in the usual manner on a Wide substantial crank chamber or entablature g, which is in turn mounted upon a base chamber 72., all in accordance with well known practice.

I provide a substantial rocking lever or 'beam and pivot same at a point j midway between the two cylinders, this-beam i being in duplicate for constructional urposes. f

The lower end of each artic-u ated piston rod is secured to one end of the rocking lever or beam 2', while one end of the said beam is connected by means of a conventional connectin ,rod is to a crank 10' of suitable throw, and p aced approximately immediately under the cylinder at.

I prefer to make the rocking levers i of such a length that at no time during the stroke of the piston does the centre of the point of attachment of either articulated piston rods e or f to the rocking lever 71 pass the axis of the corresponding cylinder a or b.

The object of this arrangement is to provide for the resultant side thrust of the con necting rod on the piston to always be in one direction, and further that this side thrust may always press the piston on to the scavenging air admission ort l and su ercharge air port m in t e cylinder, w ich ports it is a great advantage to always keep sealed so as to in air.

prevent-the escape of scavengother advantage of using this side of the cylinder as a guide surface is that the inlet side of the cylinders of two-stroke cycle engines of this kind is always the coolest and best lubricated, alothough, in this connection it will be realized that the conpared with the usual trunk piston. Thus the attachment of the piston rods e and f to the ends of a rocking lever such as i is a principle that has, to a very considerable measure, the advantages of the msual crosshead system.

This construction produces in effect an inverted two cylinder beam engine of the known type. a

It is to be understood that I do not limit the number of units which I ma employ, each consisting of a pair of cylin ers a1 and b, rockin levers i and one crank is forming a unit. either is the invention to be limited to the use of a single-acting or even a trunk-piston engine.

In appl ing my invention tothis well known and tried mechanism I make use of the piston 01 which is remote from the crank for the purpose of driving a scavenging air pump n direct by placing the cylinder of such pump on the base chamber lb and immediately under the piston d' and connecting the said workin piston d to the piston of the air pump n y means of a rigid rod 0 of any section. adapted to .reciprocate with the iston (Z. t

T e piston of the scavenging air pump a could be single acting which would simplify the mechanism, but it would be more convenient to make it double acting and pass the rods 0 through glands in the usual manner as shown at 0' in Fig. 1.

This construction would allow an an air ump of ample'capacity to be provided, and

Further, in order to provide a satisfactory and convenient scavenging air chamber prefer to arrange the two cylinders a: andb m such manner that the air inlet ports I l,

m mare on the side nearest the centre line of the engine, while the exhaust ports 1; p

.aneon' the outside of; the engine and as .there will be a certain amount of space 9/ between the water jacket r and the tangential walls of the cylinder structure, I make used this space 9 as an air chamber into which the air from the scavenge pump 11.

air pump it and rods 0 and' will be delivered and from which it will. pass via the scavenging ports Z and m into the working cylinders an and b.

As this construction offers many for so doing I also prefer to make use of the well known gauxiliary scavenging or super-charge valve which controls a superfacilities I charge air port situated above the usual 7 scavenging port.

The scavenging port is opened by the piston on the'down stroke after the exhaust port opens and is closed by the piston on the up stroke, the super-charging air port being, however, opened under the control of the valve, after the piston has closed the.

ordinary scavenging port, the effect being that the working cylinder is supercharged by air from the supercharge air port to the amount of the back pressure set up in the scavenge system or to a higher pressure from a separate receiver if such is provided.

The convienienc'e ofiered b this arrangement is that this valves of t e rotary type,

as shown, or other suitable type,'can,be situated in the walls of the actual scavenging air chamber 9 adjacent to and between the super-charging ports mm of the two cylinders, the valve thus open s directly into the scavenging air chamber 9 which is a considerable convenience as it eliminates the necessity of any pipes and obviates the waste and annoyance of any small leaks of air or 01 The shaft t of thesaid super-charge valve 8 together with fuel pumps, air starting valves, etc.', would be driven from a lay shaft (not'shown') which in turn would becontrolled for adjustment in the usual manner. 1 It will, therefore, be seen that each engine unit may consist of two cylinders a'and b with their pistons c d and piston rods 0, f, rocking beam i,'main connectingrod is crank shaft with single crank k, and a' suitable entab'lature g and base plate Incomplete with air scavenging pump n,'rigid rod 0 and all necessary valves, otherwise 'a complete en inc.

' prefer to form the cylinders a and b with a large rectangular flange u at both the top and the bottom and to provide two bolting flanges arranged vertically at each side and at top and bottom in such a manner that:

any number of pairs ofcylinders can be bolted together and mounted on crank chamber sections, also bolted together, so as to form a one',:two,' three or four crank engine. or as may be required, and the improved construction allows this to be done very readily, for example, in a multi-crank engine, a cover plate, such as o, can be attached on the outside of the end pairs of cylinders and A the spaces between the cylinders would form part of one common scavenging air chamber.

q while'one shaft it. would. pass through the valve chests and'drive all the rotary supercharge valves 8. Therefore the construction provides the very great convenience of allowing engines having any number of cranks or units to be built up of units entirely with the exception of the bed plates and crank shafts.

\Vhat I claim as my invention and desire to secure by Letters Patent is 1. A two stroke Diesel engine of the inverted beam type embodying a. pair of cylinders, and inverted beam and a scavenging air pump and comprising the combination of two cylinders connected one to each end of the beam, the end of the beam under one cylinder being connected to the crank means whereby the piston of that cylinder' connected to the other end of the beam is put in driving connection with the scavenging air pump independently of the beam, a scavengin air chamber formed by the space between t e two cylinders and .plates secured to side, top and bottom flanges on the cylinder structure, means for, connectingthe discharge of the scavenging air pump to said scavenging air. chamber, scavenging air ports and supercharging air ports formed in the o posing walls of the adjacent pair of cylin ers, a rotary valve located in the scavenging air chamber and controlling the supercharging air ports of the cylinders, a shaft passing through the scavenging air chamber and rotary valve for operating the latter, and means for operating said shaft.

2. A. two stroke Diesel engine of the inverted beam type embodying a pair of cylinders, an inverted beam and a scavenging air pump and comprising the combination of two cylinders connectedone to each end of the 'beam, the end of the beam under one cylinder being connected to the crank, means whereby the piston of that cylinder connected to the other end of the beam is put in driving connection with the scavenging air pump. independently of the beam, a scavenglng air chamber formed by the space between the two cylinders, means for connectlng the discharge of the scavenging air pump to said scavenging air chamber, scavenging air ports and supercharging air ports formed in the opposing walls of the adjacent pair of cylinders, a rotary valve located in the scavenging air chamber and controlling the supercharging air ports of the cylinders, a shaft passing through the scavenging air chamber and rotary valve for operating the latter, and means for operating saidshaft.

3. A two stroke Diesel engine of the in verted beam type embodying a pair of cylinders, a beam and a scavenging air pump and comprising the combination oftwo cylinders, the pistons of which are connected one to each end of the beam, the end of the beam under one cylinder being connected to the crank, a rod whereby the piston of formed by the space between the two cylinders and plates secured to side top and bottom flanges on the cylinder structure, means for connecting the discharge of the scavenging air pump to said scavenging air chamber, scavenging air ports and supercharging air ports formed in the opposing walls of the adjacent pair of cylinders, a rotary valve located in the scavenging air chamber and controlling the supercharging air ports of the cylinders, a shaft passing through the scavenging air chamber and rotary valve for operating the latter and means for operating said shaft,

'4. A two stroke Diesel engine of the inverted beam type'embodying a pair of cylinders, a beam and a scavenging air pumpand comprislng a unitary structure consistand bottom flanges on the cylinder structure,

and whereby said plates and the flanges to which they aresecured permit of a plurality of the said unitary structure being bolted together and provided with .a scavenging air chamber common to all the cylinders of the assembled units, means for connecting.

the discharge'of the scavenging air pump to the-scavenging air chamber, scavenging air .ports and supercharging air ports formed in the opposing walls of the cylinders, a rotary valve located in the scavenging air chamber and controlling the supercharging air ports of the cylinders, a shaft passing through the scavenging air chamberv and rotary, valve for operating the latter, and means for operating said shaft.

5. A two stroke Diesel engine of the inverted beam type embodying a pair of cylinders, a beam and a scavenging air pump and comprising. a unitary structure consisting of two cylinders the pistons of which are connected one to each end of the beam, the end of the beam under one cylinder being connected to the crank, a rod whereby the piston of that cylinder connected to the other-end of the beam is put in driving connection with the scavenging air pump independently of the beam, a scavenging air .top and bottom flanges on the cylinder structure, and whereby said plates the flanges to which they are secured permit of a pluin the opposing walls of the cylinders, a rality 01E the said nnitar structures being rotar valve located in the scavenging air 10 bolted together and provi ed with a sc'avengchem rand controlling the snpercharging ing air chamber common to all the cylinders air ports of the cylinders, a shaft passing 5 of the assembled units, means for connecting through the scavenging air chamber and rothe discharge of the scavenging air" pump tary valve for. operating the latter, and to the scavenging air chamber, scavenging means for 0 erating said shaft. air ports and supercharging air ports formed ART FREDERICK EVANS. 

